Another way is to look as much like a car as possible, which some larger motorcycles can pull off. I hadn't seen anyone do the bright buckets trick, I bet it works decently well. As you say, looking dangerous may be more important than being "noticeable".

Well said. I think a person on a bicycle can help drivers notice him/her by looking as wide and bright as possible at a glance. I have white buckets mounted on my rear rack with red/white retroreflective safety tape all over them, which seems to help. If a driver is only processing unexpected objects in broad terms and catches sight of an object that looks big enough to ruin their day, it might get bumped up to a higher level of attention. At least that's consistent with how I process information behind the wheel.

I don't mean to imply that it's a good thing. Rather, that it may be something they are completely unaware is happening in their brain, as it takes place outside of conscious thought. It may be something they don't have any control over, and they wouldn't be aware it's happening unless someone teaches them to notice it, like change blindness.

That means it would likely take some careful training to teach their brains to work differently.

It also means they aren't being "sloppy" in the sense of laziness. They may be very attentive, in fact, but if some things entering their senses are processed out as garbage before they are conscious of it, they can't actively pay attention to that thing, regardless of their level of attentiveness.

I can accept that they were too focused on the road and themselves to pay attention to anything but cars and traffic controls, but I don't consider that in any way a legitimate excuse for not maintaining an adequate lookout. There's too much driver complacency about safety. People need to stay sharp when they have the power to end someone's life in a second. A motor vehicle at speed is too much power to get sloppy with.